Seismic wave amplification in the central Indo-Gangetic Plains, India, estimated from the ratio of soft to hard site source spectrum

The ratio of source spectrum to the geometric mean source spectrum of the same event from sites in the the Indo-Gangetic Plains (IGP) are determined. A comparison of spectral amplification estimated via both the traditional SSR and new RSS techniques at four sites show that they resemble each other fairly well but also reveal significant differences, which are attributable to the techniques themselves. The SSR technique is clearly preferable if this input motion is site-specific to the reference hard site. If, on the other hand, the ground motion can only be specified at a generic hard site (as is often the case), then the RSS technique may a better option. In common with several previous studies, we find that teleseismic recordings may be useful in the estimation of low-frequency (f < 0.5 Hz) spectral amplification in the IGP. The spectral amplifications, now available at 35 IGP sites, are spread over ~ 1000 km. In view of the extremely high seismic exposure of IGP from large/great earthquakes along the Himalayan arc, the importance of detailed knowledge of the basin’s seismic response can hardly be overemphasized.

Figure Caption: Location of study

 

Citation: S. K. Singh, X. Pérez-Campos, D. Srinagesh : D. Srinivas : G. Suresh : R. K. Chadha, G. Suresh; 2020; Seismic wave amplification in the central Indo-Gangetic Plains, India, estimated from the ratio of soft to hard site source spectrum; J Seismol (2020) 24:679–692, https://doi.org/10.1007/s10950-020-09931-6